/**
 * 文件剪贴板 Composable（应用内内存态单例）
 * 复制/剪切 → 粘贴到其他目录；粘贴动作由 index.vue 执行
 */

import { ref, computed } from 'vue'
import type { FileItem } from '@/types/file-system'

export type ClipboardMode = 'copy' | 'cut'

interface FileClipboardState {
  mode: ClipboardMode
  items: FileItem[]
  fromDir: string
}

// 模块级单例状态（跨组件共享）
const state = ref<FileClipboardState | null>(null)

export function useFileClipboard() {
  const clipboard = computed(() => state.value)

  const clipboardEmpty = computed(() => !state.value || state.value.items.length === 0)

  /** 设置复制项 */
  const setCopy = (items: FileItem[], fromDir: string) => {
    state.value = { mode: 'copy', items: [...items], fromDir }
  }

  /** 设置剪切项 */
  const setCut = (items: FileItem[], fromDir: string) => {
    state.value = { mode: 'cut', items: [...items], fromDir }
  }

  /** 清空剪贴板 */
  const clear = () => {
    state.value = null
  }

  return { clipboard, clipboardEmpty, setCopy, setCut, clear }
}